The World Wildlife Fund (WWF) has issued a call to expand the number and size of marine reserves where fishing is banned.

The report's authors looked at a wide range of reservesCallum Roberts

It says that such reserves are often effective in allowing a rapid recovery of fish stocks depleted by fishing.

The overspill of fish and marine animal stocks out of such reserves and into unprotected areas proves to be a quick benefit for the fishing industry, it says.

WWF supported a review of a range of scientific data on marine reserves which came to the conclusion that fish stocks recovered most efficiently when 20-40% of the habitat of the fish concerned was turned into a no-fishing zone.

Controversial policy

Fiona Gell and Callum Roberts of the environmental department of the University of York, UK, publish their review of the evidence on marine reserves in the journal Trends in Ecology and Evolution.

Golden groupers like this are protected in the CaribbeanCallum Roberts

"Using marine reserves for fisheries management is controversial.

"Critics argue that most commercial species are too mobile to benefit, that marine reserves are only appropriate in very specific cases and that it is too risky to implement marine reserves as fisheries management tools on a larger scale until we have more experimental proof of their efficacy," they write.

But, say the authors, more and more experimental evidence is pointing towards the conclusion that no-fishery zones do work.

Spillover benefit

Fish in protected areas survive longer and produce more young.

The young fish spill outside the reserve and increase stocks available for fishery, a range of studies seem to indicate.

Dog snappers gather to spawn in a reserve in BelizeCallum Roberts

"Fishers have nothing to fear from marine reserves," says Professor Roberts, "but they should worry about a future without them."

Dr Gell and Professor Roberts reviewed the evidence from dozens of marine reserves.

They say even fish which travel long distances and hence would be expected to benefit least from protection still do enjoy a recovery.

They cite the example of the protection of the spawning grounds of a grouper fish in the US Virgin Islands where a relatively small reserve led to a swift increase in average fish size.

Similar measures could be useful to protect cod spawning grounds, they say.